A method for preparing methacrylic acid

Abstract

The present invention relates to a method for preparing methacrylic acid, and in particular to a method for synthesizing methacrylic acid from methyl propionate, water and oxygen. The process is carried out in a fixed bed reactor, and on a multifunctional catalyst, methyl propionate is first hydrolyzed with water to generate equimolar propionic acid and methanol, and at the same time, the methanol generated in situ is oxidized on the catalyst to generate formaldehyde, and then the formaldehyde and propionic acid are condensed to generate methacrylic acid.

Description

Technical Field

[0001] The invention relates to a method for preparing methacrylic acid, in particular to a method for preparing methacrylic acid from methyl propionate, H2O and oxygen. Background Art

[0002] Methacrylic acid (MAA) is an important chemical raw material. It has two functional groups, a carbon-carbon double bond and a carboxylic acid group, and can undergo polymerization and esterification reactions. It can be used to prepare methyl methacrylate, coatings, synthetic rubber, adhesives, fabric treatment agents, resins, polymer material additives, and functional polymer materials.

[0003] The production of methacrylic acid in China is only an auxiliary link in the production of methyl methacrylate (MMA). There are basically no large-scale facilities in China that specialize in the production of methacrylic acid. The current production of MAA by foreign manufacturers is estimated to be around 100,000 tons.

[0004] my country mainly adopts the acetone cyanohydrin method to produce MMA. Unlike foreign countries, domestic large-scale MMA production facilities basically do not produce MAA. At present, methacrylic acid is basically produced by small-scale manufacturers, which basically do not adopt the circular economy model. They mainly include Suzhou Amway Chemical Factory, Shanghai Pen Chemical Factory, Changzhou Tianyun Chemical Co., Ltd., Liyang Feida Electrochemical Equipment Factory, Jiangsu Changlong Chemical Co., Ltd. Changzhou Organic Chemical Products, Xi'an Organic Chemical Factory, Liyang Zhengda Chemical Co., Ltd., Shanghai Lisheng Chemical Factory, Zhejiang Youhao Chemical Industry Co., Ltd., Zhejiang Fuyang Yufeng Chemical Co., Ltd., Liyang Hengsen Chemical Co., Ltd., Jiangsu Zecheng Chemical Co., Ltd., etc. Most products are of poor quality, with many impurities, high water content, darker color, high activity, short storage period, high production cost, and difficult to meet the actual production needs of the country, and need to be imported every year.

[0005] At present, the total demand for methacrylic acid in my country is about 18,000-20,000t / a, the total production capacity is about 16,000t / a, the actual output is about 15,000t / a, and the gap is about 5,000 tons. The main consumption is in coatings, namely acrylic coatings, 30%-40% (accounting for the total), followed by adhesives, textile and fiber processing aids, leather, paper and other industries. The main consumption area of ​​methacrylic acid in China is Guangdong Province, accounting for more than 60% of the country.

[0006] At present, the main production methods of methacrylic acid include acetone cyanohydrin method, isobutylene or isobutane oxidation method, ethylene carbonylation method and propylene carbonylation method.

[0007] The acetone cyanohydrin method (ACH method) for preparing methacrylic acid (MAA) was first industrialized. This route uses acetone to react with HCN to generate acetone cyanohydrin, which reacts with concentrated mercaptan to generate methacrylic acid amine sulfate, which is hydrolyzed to obtain MAA. However, this route uses highly toxic hydrocyanic acid as a raw material, requires highly corrosive sulfuric acid as a reactant, and also produces solid waste ammonium bisulfate during the production process. The environmental pollution is serious, and the atomic utilization rate of this process is only 47%, which is far from meeting the requirements of green chemistry.

[0008] Isobutylene (tert-butyl alcohol) oxidation method: isobutylene or tert-butyl alcohol is oxidized to methacrolein (MAL), and then oxidized to make methacrylic acid. This route has a long process flow, complex equipment, high investment, expensive raw material high-purity isobutylene, low overall selectivity, and high production cost. The isobutane method obtains isobutylene through dehydrogenation, and then obtains MAA through two-step oxidation. This technology is still in the experimental stage, with low isobutane conversion rate (~30%), and low MAL and MAA yields (less than 50%).

[0009] The ethylene carbonylation method uses ethylene and CO, H2 carbonyl groups to synthesize propionaldehyde, propionaldehyde and formaldehyde condense to form methacrolein, and then oxidize to obtain methacrylic acid. BASF in Germany invented this technology. The propylene carbonylation method uses propylene carbonylation to produce isobutylaldehyde, which is dehydrogenated and then oxidized to produce MAA, or first oxidized to produce isobutyl acid, and then dehydrogenated to produce MAA. Rohm companies in France and Germany have completed industrial development.

[0010] In this application, MAA is prepared by hydrolysis-oxidation-condensation with methyl propionate, water and oxygen as raw materials. There is no MAA preparation technology using this as raw material in the literature. Only similar processes are reported: Wolfgang et al. catalyzed the reaction of propionic acid and formaldehyde with K / Al2O3 / SiO2 catalyst, and the conversion rate was only 33% and the selectivity was 49%. In 1988, Mamoru Ai reported that PV catalyst was used for the condensation reaction of propionic acid and formaldehyde. The study found that when the molar ratio of propionic acid to formaldehyde was 2, the yield of methacrylic acid could reach 39 mol%. Using V-Si-P catalyst, the yield of methacrylic acid under optimized reaction conditions could reach 53 mol% and the selectivity was 82%. In 2003, Mamoru Ai reported that the yield of methacrylic acid on Sn-Si-P catalyst could reach 58%.

[0011] In summary, in the reaction of preparing methacrylic acid by reacting methyl propionate with water and oxygen, the hydrolysis-oxidation-condensation trifunctional catalyst is the key. The catalytic activity of the catalysts reported so far is generally low. Therefore, the development of novel and highly active catalysts is the key and of great significance.

[0012] The reaction process is:

[0013] Summary of the invention

[0014] The problem to be solved by the present invention is to provide a method for preparing methacrylic acid, starting from cheap, easily available and stable methyl propionate, water and oxygen, through a suitable catalyst system, and through hydrolysis-oxidation-condensation to prepare methacrylic acid.

[0015] The technical solution is:

[0016] In a fixed bed reactor, methyl propionate, water and oxygen in a certain proportion, after gasification and dilution with inert gas or without dilution, react on a certain amount of catalyst with the triple functions of hydrolysis-oxidation-condensation under certain temperature and pressure conditions to produce methacrylic acid.

[0017] The molar ratio of methyl propionate, water and oxygen is: 1:(1-10):(0.5-2);

[0018] Oxygen can be provided by pure oxygen or air;

[0019] The inert atmosphere includes: N2, Ar, He;

[0020] The inert gas accounts for 5-90% of the total volume of the total gas;

[0021] The mass space velocity of methyl propionate on the catalyst is: 0.2-4h -1 ;

[0022] Reaction temperature: 250-450°C;

[0023] Reaction pressure: 0.5-30atm.

[0024] Provide a solution:

[0025] The molar ratio of methyl propionate, water and oxygen is: 1:(1-5):(0.5-1);

[0026] The inert gas accounts for 10-70% of the total volume of the total gas;

[0027] The mass space velocity of methyl propionate on the catalyst is: 0.3-3h -1 ;

[0028] Reaction temperature: 300-400°C;

[0029] Reaction pressure: 1-15atm.

[0030] Provide a solution:

[0031] The molar ratio of methyl propionate, water and oxygen is: 1:(1-3):(0.5-0.75);

[0032] The inert gas accounts for 20-50% of the total volume of the total gas;

[0033] The mass space velocity of methyl propionate on the catalyst is: 0.3-2h -1 ;

[0034] Reaction temperature: 310-360°C;

[0035] Reaction pressure: 1-10atm.

[0036] The catalyst having the three functions of hydrolysis-oxidation-condensation has the following structural characteristics:

[0037] The first-stage component has the function of catalyzing the hydrolysis of methyl propionate; the second-stage component has the function of catalyzing the oxidation of methanol; and the third-stage component has the function of catalyzing the condensation of formaldehyde and propionic acid.

[0038] The specific properties of the catalyst with the three functions of hydrolysis-oxidation-condensation are as follows:

[0039] The first-stage component is an active component with weak to medium acidity, selected from: natural weak or medium acid clay, including kaolin, bentonite, montmorillonite, talc, natural zeolite; metal oxides, including Al2O3, Ga2O3, Cr2O3, HfO2, ZrO2, TiO2, SnO2, GeO2, Sb2O5, SiO2, MoO3; weak acid synthetic molecular sieves, including HX, HY, Hβ, SAPO-34, SAPO-11; metal phosphates (including AlPO4, FePO4, Ti3(PO4)4, Zr3(PO4)4, BiPO4, Zn3(PO4)2), and mixtures of the above-mentioned weak and medium acid catalysts;

[0040] The second-stage component is a weakly alkaline active component with oxidation function, selected from: CeO2, Pr6O 11 , Tb4O7, V2O5, Co3O4, Fe2(MoO4)3 and mixtures thereof;

[0041] The third-level component is an active component with medium to strong acidity (or alkalinity or both acidity and alkalinity), selected from: WO3, Nb2O5, Ta2O5, B2O3; Cs2O, Rb2O, SrO, CaO, BaO, La2O3, Ba(OH)2; heteropolyacids, including phosphotungstic acid, phosphomolybdic acid, silicotungstic acid; SO4 2- / TiO2、SO4 2- / ZrO2、SO4 2- / Fe2O3 and their mixtures.

[0042] In the catalyst having the triple functions of hydrolysis-oxidation-condensation, the second-stage component accounts for 15-30wt% of the total mass of the catalyst, the third-stage component accounts for 1-10wt% of the total mass of the catalyst, and the rest is the first-stage component.

[0043] The preparation method of the catalyst with the three functions of hydrolysis-oxidation-condensation is: first prepare a colloidal solution of the second-stage component, then adsorb the third-stage component onto the colloid of the second component, and finally load the colloid adsorbed with the third-stage component onto the first-stage component through electrostatic adsorption or impregnation, and finally calcine, the calcination temperature is 400-800°C, the calcination time is 4-24h, and the calcination atmosphere is air, or an oxygen-containing (5-99.9%) inert atmosphere.

[0044] The process is carried out in a fixed bed reactor. On a multifunctional catalyst, methyl propionate is first hydrolyzed with water to produce equimolar propionic acid and methanol. At the same time, the methanol generated in situ is oxidized on the above catalyst to produce formaldehyde, and then the formaldehyde and propionic acid are condensed to produce methacrylic acid.

[0045] Beneficial technical effects

[0046] 1. The present invention realizes the synthesis of high value-added methacrylic acid by organically combining innovative catalyst design and catalytic function with cheap, readily available and simple raw materials;

[0047] 2. The catalyst has good stability and hydrothermal stability, the reaction process is simple, controllable and easy to operate, and the yield of methacrylic acid can reach up to about 75%. DETAILED DESCRIPTION

[0048] In order to further explain the present invention in detail, several specific implementation cases are given below, but the present invention is not limited to these embodiments.

[0049] Example 1

[0050] 5 g of cerium nitrate hexahydrate was dissolved in 100 mL of deionized water, 50 mL of 28% ammonia water (28% is the mass concentration, all the following examples are mass concentrations) was added to 50 mL of water, and the ammonia solution was added to the fully stirred cerium nitrate aqueous solution at a rate of 10 mL / min. The obtained colloidal solution was characterized by electron microscopy and showed that the size of the cerium oxide nanoparticles was about 40-50 nm.

[0051] To the above-mentioned cerium oxide (second-stage component) colloidal solution, (NH4)2WO4 is added according to (WO3:CeO2=1:3 mass ratio), and after stirring for sufficient adsorption, the first-stage component micron-level (1-1000 microns, the micron level in the following embodiments is all within this range) γ-Al2O3 is added to adsorb the above-mentioned cerium oxide colloid. The mass of the first-stage component added is according to (WO3:CeO2:Al2O3=1:3:6 mass ratio), and after stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and air-roasted at 500°C for 4 hours.

[0052] The obtained sample was pressed into tablets with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:1:0.5. The oxygen came from pure oxygen, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 350°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0053] Example 2 (using the catalyst sample in Example 1)

[0054] The obtained sample was pressed into tablets with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:1:1. The oxygen came from pure oxygen, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 350°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0055] Example 3 (using the catalyst sample in Example 1)

[0056] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:1:2. The oxygen came from pure oxygen, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 350°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0057] Example 4

[0058] 5 g of praseodymium nitrate hexahydrate was dissolved in 100 mL of deionized water, 50 mL of 28% ammonia water was added to 50 mL of water, and the ammonia solution was added to the fully stirred praseodymium nitrate aqueous solution at a rate of 10 mL / min. The electron microscopy characterization of the obtained colloidal solution showed that the size of the praseodymium oxide nanoparticles was about 40-60 nm.

[0059] In the above praseodymium oxide (secondary component) colloidal solution, (Nb2O5:Pr6O 11 =1:3 mass ratio) add ammonium niobium oxalate, stir and fully adsorb, then add the first-stage component micron-sized ZrO2 to adsorb the above praseodymium oxide colloid. The mass of the first-stage component added is (Nb2O5:Pr6O 11 :ZrO2=1:3:6 mass ratio), after stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and calcined at 600℃ in an atmosphere containing 5% N2 oxygen for 24h.

[0060] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:1. The oxygen came from the air, the inert dilution atmosphere was Ar, and the inert gas accounted for 20% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.2h -1 The reaction was carried out at 310°C and 1 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0061] Example 5 (using the catalyst sample in Example 4)

[0062] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:5:1. The oxygen came from the air, the inert dilution atmosphere was Ar, and the inert gas accounted for 20% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.2h -1 The reaction was carried out at 310°C and 1 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0063] Example 6 (using the catalyst sample in Example 4)

[0064] The obtained sample was pressed into tablets with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:10:1. The oxygen came from the air, the inert dilution atmosphere was Ar, and the inert gas accounted for 20% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.2h -1The reaction was carried out at 310°C and 1 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0065] Example 7

[0066] Dissolve 5g of ferric nitrate nonahydrate in 100mL of deionized water, dissolve 7.3g of ammonium molybdate in 50mL of deionized water, and add 50mL of ethylene glycol. Add the ammonium molybdate solution into the fully stirred ferric nitrate aqueous solution at a rate of 10mL / min. Electron microscopy characterization shows that the size of the iron molybdate (Fe2(MoO4)3) nanoparticles in the obtained colloidal solution is approximately 40-70nm.

[0067] To the above-mentioned iron molybdate (second-stage component) colloidal solution, silicotungstic acid is added according to (silicotungstic acid: iron molybdate = 1:5 mass ratio), and after stirring for sufficient adsorption, the first-stage component, micron-sized AlPO4, is added to adsorb the above-mentioned iron molybdate colloid. The mass of the first-stage component added is according to (silicotungstic acid: iron molybdate: AlPO4 = 1:5:35 mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and air-roasted at 500°C for 4 hours.

[0068] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 5% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.3h -1 The reaction was carried out at 360°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0069] Example 8 (using the catalyst sample in Example 7)

[0070] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 10% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.3h -1 The reaction was carried out at 360°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0071] Example 9 (using the catalyst sample in Example 7)

[0072] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.3h -1 The reaction was carried out at 360°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0073] Example 10 (using the catalyst sample in Example 7)

[0074] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 70% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.3h -1 The reaction was carried out at 360°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0075] Example 11 (using the catalyst sample in Example 7)

[0076] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 90% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.3h -1 The reaction was carried out at 360°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0077] Example 12

[0078] 5 g of praseodymium nitrate hexahydrate and terbium nitrate hexahydrate (mass ratio 1 / 3) were dissolved in 100 mL of deionized water, 50 mL of 28% ammonia water was added to 50 mL of water, and the ammonia solution was added to the fully stirred mixed aqueous solution of praseodymium nitrate and terbium nitrate at a rate of 10 mL / min. The obtained mixed colloidal solution was characterized by electron microscopy and showed that the size of the mixed nanoparticles of praseodymium oxide and terbium oxide was about 40-70 nm.

[0079] In the colloidal solution of the above-mentioned mixture of praseodymium oxide and terbium oxide (second-stage component), ((WO3+Nb2O5):(Pr6O 11+Tb4O7)=1:3 mass ratio), add (NH4)2WO4 and ammonium niobium oxalate (mass ratio 1 / 5), stir for sufficient adsorption, then add the first-stage component micron-sized Zr3(PO4)4 to adsorb the above-mentioned praseodymium oxide and terbium oxide mixed colloid, the mass of the added first-stage component is according to (third-stage component: second-stage component: first-stage component=1:3:6 mass ratio), stir for sufficient adsorption, filter, wash thoroughly, dry, and air-roast at 600℃ for 4h.

[0080] The obtained sample was pressed into tablets with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was He, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.2h -1 The reaction was carried out at 350°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0081] Example 13 (using the catalyst sample in Example 12)

[0082] The obtained sample was pressed into tablets with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was He, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 0.3h -1 The reaction was carried out at 350°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0083] Example 14 (using the catalyst sample in Example 12)

[0084] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was He, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 2h -1 The reaction was carried out at 350°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0085] Example 15 (using the catalyst sample in Example 12)

[0086] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was He, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 3h -1 The reaction was carried out at 350°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0087] Example 16 (using the catalyst sample in Example 12)

[0088] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:3:0.75. The oxygen came from the air, the inert dilution atmosphere was He, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 4h -1 The reaction was carried out at 350°C and 5 atm and monitored online by gas chromatography. The product yield and selectivity after 8 h of reaction are shown in Table 1.

[0089] Embodiment 17

[0090] 5 g of terbium nitrate hexahydrate was dissolved in 100 mL of deionized water, 50 mL of 28% ammonia water was added into 50 mL of water, and the ammonia solution was added into the fully stirred terbium nitrate aqueous solution at a rate of 10 mL / min. The obtained colloidal solution contained terbium oxide nanoparticles with a size of about 50-70 nm as shown by electron microscopy.

[0091] Strontium nitrate and barium nitrate (mass ratio 1 / 1) are added to the above-mentioned terbium oxide (second-stage component) colloidal solution according to ((SrO+BaO):Tb4O7=1:3 mass ratio), and after stirring for sufficient adsorption, the first-stage component micron-sized SnO2-Al2O3 (SnO2:Al2O3=1:1 mass ratio) is added to adsorb the above-mentioned terbium oxide colloid. The mass of the added first-stage component is (third-stage component: second-stage component: first-stage component=1:3:6 mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and air-roasted at 700°C for 4 hours.

[0092] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1The reaction was carried out at 250°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0093] Example 18 (using the catalyst sample in Example 17)

[0094] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 300°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0095] Example 19 (using the catalyst sample in Example 17)

[0096] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0097] Example 20 (using the catalyst sample in Example 17)

[0098] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 400°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0099] Example 21 (using the catalyst sample in Example 17)

[0100] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 450°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0101] Embodiment 22

[0102] 5 g of praseodymium nitrate hexahydrate was dissolved in 100 mL of deionized water, 50 mL of 28% ammonia water was added to 50 mL of water, and the ammonia solution was added to the fully stirred praseodymium nitrate aqueous solution at a rate of 10 mL / min. The electron microscopy characterization of the obtained colloidal solution showed that the size of the praseodymium oxide nanoparticles was about 40-60 nm.

[0103] In the above praseodymium oxide (secondary component) colloidal solution, (SrO:Pr6O 11 =1:3 mass ratio) add strontium nitrate, stir and fully adsorb, then add the first-stage component micron-sized HfO2 to adsorb the above praseodymium oxide colloid. The mass of the first-stage component added is (SrO:Pr6O 11 :HfO2=1:3:6 mass ratio), after stirring for sufficient adsorption, filter, wash thoroughly, dry, and calcine in air at 600℃ for 4h.

[0104] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 0.5 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0105] Example 23 (using the catalyst sample in Example 22)

[0106] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1The reaction was carried out at 360°C and 1 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0107] Example 24 (using the catalyst sample in Example 22)

[0108] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 10 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0109] Example 25 (using the catalyst sample in Example 22)

[0110] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 15 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0111] Example 26 (using the catalyst sample in Example 22)

[0112] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 30 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0113] Embodiment 27

[0114] 5 g of terbium nitrate hexahydrate was dissolved in 100 mL of deionized water, 50 mL of 28% ammonia water was added into 50 mL of water, and the ammonia solution was added into the fully stirred terbium nitrate aqueous solution at a rate of 10 mL / min. The obtained colloidal solution contained terbium oxide nanoparticles with a size of about 50-70 nm as shown by electron microscopy.

[0115] NaTaO3 is added to the terbium oxide (second-stage component) colloidal solution according to (Ta2O5:Tb4O7=1:3 mass ratio), and after stirring for sufficient adsorption, the first-stage component micron-sized TiO2 is added to adsorb the above-mentioned terbium oxide colloid. The mass of the first-stage component added is (third-stage component: second-stage component: first-stage component=1:3:6 mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and calcined at 800°C in an argon atmosphere containing 10% oxygen for 12 hours.

[0116] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0117] Embodiment 28

[0118] Dissolve 5 g of vanadium oxalate in 100 mL of deionized water, take 50 mL of 28% ammonia water and add it into 50 mL of ethylene glycol. Add the ammonia solution into the fully stirred vanadium oxalate aqueous solution at a rate of 10 mL / min. The obtained mixed colloidal solution is characterized by electron microscopy and shows that the size of the vanadium oxide nanoparticles is about 40-60 nm.

[0119] Ammonium borate is added to the above-mentioned vanadium oxide (second-stage component) colloidal solution according to (B2O3:V2O5=1:3 mass ratio), and after stirring for sufficient adsorption, the first-stage component, micron-sized SnO2, is added to adsorb the above-mentioned vanadium oxide colloid. The mass of the first-stage component added is according to (third-stage component: second-stage component: first-stage component=1:3:6 mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and calcined at 500°C in an atmosphere of 99.9% oxygen and nitrogen for 4 hours.

[0120] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0121] Embodiment 29

[0122] Dissolve 5 g of vanadium oxalate in 100 mL of deionized water, take 50 mL of 28% ammonia water and add it into 50 mL of ethylene glycol. Add the ammonia solution into the fully stirred vanadium oxalate aqueous solution at a rate of 10 mL / min. The obtained mixed colloidal solution is characterized by electron microscopy and shows that the size of the vanadium oxide nanoparticles is about 40-60 nm.

[0123] To the above vanadium oxide (second-stage component) colloidal solution, RbNO3 is added according to (Rb2O:V2O5=1:3 mass ratio), and after stirring for sufficient adsorption, the first-stage component, micron-sized MoO3, is added to adsorb the above vanadium oxide colloid. The mass of the first-stage component added is according to (third-stage component: second-stage component: first-stage component=1:3:6 mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and calcined at 500°C in air atmosphere for 4 hours.

[0124] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0125] Embodiment 30

[0126] Dissolve 5 g of cobalt nitrate in 100 mL of deionized water, take 50 mL of 28% ammonia water and add it to 50 mL of glycerol, add the ammonia solution into the fully stirred cobalt nitrate aqueous solution at a rate of 10 mL / min, and the obtained mixed colloidal solution is characterized by electron microscopy, which shows that the size of the cobalt oxide nanoparticles is about 30-50 nm.

[0127] To the above cobalt oxide (second-stage component) colloidal solution, CsCO3 is added according to (Cs2O:Co3O4=1:3 by mass ratio), and after stirring for sufficient adsorption, the first-stage component, micron-sized GeO2, is added to adsorb the above cobalt oxide colloid. The mass of the first-stage component added is according to (third-stage component: second-stage component: first-stage component=1:3:6 by mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and calcined at 500°C in air atmosphere for 4 hours.

[0128] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h-1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0129] Embodiment 31

[0130] 5 g of cerium nitrate hexahydrate was dissolved in 100 mL of deionized water, 50 mL of 28% ammonia water was added into 50 mL of water, and the ammonia solution was added into the fully stirred cerium nitrate aqueous solution at a rate of 10 mL / min. The obtained mixed colloidal solution was characterized by electron microscopy and showed that the size of the mixed nanoparticles of praseodymium oxide and cerium oxide was about 40-70 nm.

[0131] In the colloidal solution of the mixed praseodymium oxide and cerium oxide (secondary component), (CaO:(Pr6O 11 +CeO2)=1:3 mass ratio), add calcium nitrate, stir and fully absorb, then add the first-stage component micron-sized Sb2O5 to absorb the above-mentioned praseodymium oxide and cerium oxide mixed colloid, the mass of the first-stage component added is according to (third-stage component: second-stage component: first-stage component=1:3:6 mass ratio), stir and fully absorb, filter, fully wash, dry, and air roast at 600℃ for 4h.

[0132] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0133] Embodiment 32

[0134] 5 g of praseodymium nitrate hexahydrate was dissolved in 100 mL of deionized water, 50 mL of 28% ammonia water was added to 50 mL of water, and the ammonia solution was added to the fully stirred praseodymium nitrate aqueous solution at a rate of 10 mL / min. The electron microscopy characterization of the obtained colloidal solution showed that the size of the praseodymium oxide nanoparticles was about 40-60 nm.

[0135] In the above praseodymium oxide (secondary component) colloidal solution, (BaO:Pr6O 11 =1:3 mass ratio) add barium nitrate, stir and fully adsorb, then add the first-stage component micron-sized Ga2O3 to adsorb the above praseodymium oxide colloid. The mass of the first-stage component added is (BaO:Pr6O 11:Ga2O3=1:3:6 mass ratio), after stirring for sufficient adsorption, it was filtered, washed thoroughly, dried, and calcined at 600℃ in air atmosphere for 24h.

[0136] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0137] Embodiment 33

[0138] Dissolve 5 g of cerium nitrate hexahydrate in 100 mL of deionized water, take 50 mL of 28% ammonia water and add it into 50 mL of water. Add the ammonia solution into the fully stirred cerium nitrate aqueous solution at a rate of 10 mL / min. Electron microscopy characterization of the obtained colloidal solution shows that the size of the cerium oxide nanoparticles is about 40-50 nm.

[0139] Lanthanum nitrate is added to the above-mentioned cerium oxide (second-stage component) colloidal solution according to (La2O3:CeO2=1:3 mass ratio), and after stirring for sufficient adsorption, the first-stage component, micron-grade kaolin, is added to adsorb the above-mentioned cerium oxide colloid. The mass of the first-stage component added is (La2O3:CeO2:kaolin=1:3:6 mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and air-roasted at 500°C for 4 hours.

[0140] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0141] Embodiment 34

[0142] Dissolve 5 g of cerium nitrate hexahydrate in 100 mL of deionized water, take 50 mL of 28% ammonia water and add it into 50 mL of water. Add the ammonia solution into the fully stirred cerium nitrate aqueous solution at a rate of 10 mL / min. Electron microscopy characterization of the obtained colloidal solution shows that the size of the cerium oxide nanoparticles is about 40-50 nm.

[0143] To the above cerium oxide (second-stage component) colloidal solution, barium nitrate is added according to (Ba(OH)2:CeO2=1:3 by mass ratio), and after stirring for sufficient adsorption, the first-stage component, micron-sized calcium zeolite, is added to adsorb the above cerium oxide colloid. The mass of the first-stage component added is (Ba(OH)2:CeO2:Al2O3=1:3:6 by mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and air-roasted at 400°C for 4 hours.

[0144] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0145] Embodiment 35

[0146] 5 g of ferric nitrate nonahydrate was dissolved in 100 mL of deionized water, 7.3 g of ammonium molybdate was dissolved in 50 mL of deionized water, and 50 mL of ethylene glycol was added. The ammonium molybdate solution was added to the fully stirred ferric nitrate aqueous solution at a rate of 10 mL / min to obtain a mixed colloidal solution. Electron microscopy showed that the size of the iron molybdate nanoparticles was approximately 40-70 nm.

[0147] To the above iron molybdate (second-stage component) colloidal solution, phosphotungstic acid is added according to (phosphotungstic acid: iron molybdate = 1:5 mass ratio), stirred for sufficient adsorption, and then the first-stage component micron-grade HY is added to adsorb the above iron molybdate colloid. The mass of the first-stage component added is (phosphotungstic acid: iron molybdate: HY = 1:5:35 mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and air-roasted at 500°C for 4 hours.

[0148] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0149] Embodiment 36

[0150] 5 g of ferric nitrate nonahydrate was dissolved in 100 mL of deionized water, 7.3 g of ammonium molybdate was dissolved in 50 mL of deionized water, and 50 mL of ethylene glycol was added. The ammonium molybdate solution was added to the fully stirred ferric nitrate aqueous solution at a rate of 10 mL / min to obtain a mixed colloidal solution. Electron microscopy showed that the size of the iron molybdate nanoparticles was approximately 40-70 nm.

[0151] In the above iron molybdate (second-stage component) colloidal solution, phosphomolybdic acid is added according to (phosphotungstic acid: iron molybdate = 1:5 mass ratio), stirred for sufficient adsorption, and then the first-stage component micron-sized SAPO-34 is added to adsorb the above iron molybdate colloid. The mass of the first-stage component added is (phosphomolybdic acid: iron molybdate: HY = 1:5:35 mass ratio). After stirring for sufficient adsorption, it is filtered, washed thoroughly, dried, and air-roasted at 500°C for 4h.

[0152] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0153] Embodiment 37

[0154] Dissolve 5 g of cobalt nitrate in 100 mL of deionized water, take 50 mL of 28% ammonia water and add it to 50 mL of glycerol, add the ammonia solution into the fully stirred cobalt nitrate aqueous solution at a rate of 10 mL / min, and the obtained mixed colloidal solution is characterized by electron microscopy, which shows that the size of the cobalt oxide nanoparticles is about 30-50 nm.

[0155] In the above cobalt oxide (secondary component) colloidal solution, (SO4 2- / TiO2:Co3O4=1:15 mass ratio) add 15wt% SO4 2- / TiO2, after stirring for sufficient adsorption, add the first-stage component micron-sized Ti3(PO4)4 to adsorb the above cobalt oxide colloid, the mass of the added first-stage component is according to (third-stage component: second-stage component: first-stage component = 1:15:84 mass ratio), after stirring for sufficient adsorption, filter, wash thoroughly, dry, and calcine at 500℃ in air atmosphere for 4h.

[0156] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0157] Embodiment 38

[0158] Dissolve 5 g of cobalt nitrate in 100 mL of deionized water, take 50 mL of 28% ammonia water and add it to 50 mL of glycerol, add the ammonia solution into the fully stirred cobalt nitrate aqueous solution at a rate of 10 mL / min, and the obtained mixed colloidal solution is characterized by electron microscopy, which shows that the size of the cobalt oxide nanoparticles is about 30-50 nm.

[0159] In the above cobalt oxide (secondary component) colloidal solution, (SO4 2- / ZrO2:Co3O4=1:15 mass ratio) add 40wt% SO4 2- / ZrO2, after stirring for sufficient adsorption, add the first-stage component micron-sized Zn3(PO4)2 to adsorb the above cobalt oxide colloid, the mass of the added first-stage component is according to (third-stage component: second-stage component: first-stage component = 1:15:84 mass ratio), after stirring for sufficient adsorption, filter, wash thoroughly, dry, and calcine at 500℃ in air atmosphere for 4h.

[0160] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0161] Embodiment 39

[0162] Dissolve 5 g of cobalt nitrate in 100 mL of deionized water, take 50 mL of 28% ammonia water and add it to 50 mL of glycerol, add the ammonia solution into the fully stirred cobalt nitrate aqueous solution at a rate of 10 mL / min, and the obtained mixed colloidal solution is characterized by electron microscopy, which shows that the size of the cobalt oxide nanoparticles is about 30-50 nm.

[0163] In the above cobalt oxide (secondary component) colloidal solution, (SO4 2- / Fe2O3:Co3O4=1:15 mass ratio) add 5wt% SO4 2- / Fe2O3, after stirring for sufficient adsorption, add the first-stage component micron-sized BiPO4 to adsorb the above cobalt oxide colloid, the mass of the added first-stage component is according to (third-stage component: second-stage component: first-stage component = 1:15:84 mass ratio), after stirring for sufficient adsorption, filter, wash thoroughly, dry, and calcine at 500℃ in air atmosphere for 4h.

[0164] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0165] Comparative Example 1

[0166] La2O3, CeO2 and kaolin were mechanically mixed and ball-milled in a mass ratio of 1:3:6, and then calcined at 500°C in air atmosphere for 4 hours.

[0167] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0168] Comparative Example 2

[0169] Disperse micron-sized kaolin in 200 mL of deionized water, add lanthanum nitrate according to (La2O3: kaolin = 1:6 mass ratio), stir for sufficient adsorption, filter, wash thoroughly, dry, and calcine in air at 500°C for 4 hours.

[0170] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h-1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0171] Comparative Example 3

[0172] Dissolve 5 g of cerium nitrate hexahydrate in 100 mL of deionized water, take 50 mL of 28% ammonia water and add it into 50 mL of water. Add the ammonia solution into the fully stirred cerium nitrate aqueous solution at a rate of 10 mL / min. Electron microscopy characterization of the obtained colloidal solution shows that the size of the cerium oxide nanoparticles is about 40-50 nm.

[0173] Micron-sized kaolin was added to the above cerium oxide (second-stage component) colloidal solution at a mass ratio of (CeO2: kaolin = 1:2), stirred for sufficient adsorption, filtered, washed thoroughly, dried, and calcined in air at 500°C for 4 hours.

[0174] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0175] Comparative Example 4

[0176] 5 g of cerium nitrate hexahydrate and lanthanum nitrate hexahydrate were dissolved in 100 mL of deionized water at a mass ratio of (La2O3:CeO2=1:3), 50 mL of 28% ammonia water was added into 50 mL of water, and the ammonia solution was added into the fully stirred mixed aqueous solution at a rate of 10 mL / min. The obtained colloidal solution was characterized by electron microscopy and showed that the size of the mixed nanoparticles of cerium oxide and lanthanum oxide was about 40-60 nm.

[0177] Micron-sized kaolin was added to the mixed colloidal solution to adsorb the cerium oxide colloid. The mass ratio of the added kaolin was (La2O3:CeO2:kaolin = 1:3:6). After stirring for sufficient adsorption, the solution was filtered, washed thoroughly, dried, and calcined in air at 500°C for 4 hours.

[0178] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h-1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0179] Comparative Example 5

[0180] Preparation of the Secondary Component AgZn Alloy Colloid

[0181] Silver nitrate and zinc nitrate hexahydrate were dissolved in 100 mL of deionized water in a molar ratio of 3:1. Glycerol was added according to its reaction with metal ions (Ag + and Zn 2+ ) total molar ratio of 10:1, add to the above solution, and stir evenly. Dissolve ammonium carbonate in 100mL deionized water (the molar ratio of ammonium carbonate to the total amount of metal ions is 8:1), and then add it to the above metal ion solution at a rate of 10mL / min. The resulting precipitate is a mixed colloidal solution of silver hydroxide and zinc hydroxide. Electron microscopy characterization shows that the size of the mixed nanoparticles is about 40-60nm.

[0182] Add the third-stage component precursor ammonium borate to the above-mentioned second-stage component colloidal solution, stir for sufficient adsorption, and then add the first-stage component TiO2 to the above-mentioned second-stage component colloidal solution that has adsorbed the third-stage component precursor; the amount of the above-mentioned components added is calculated according to the mass ratio of the corresponding active components, first-stage component TiO2: second-stage component AgZn alloy: third-stage component B2O3 = 85:10:5; after stirring for sufficient adsorption, filter, wash thoroughly, dry, and roast at 500°C in N2 containing 10H2 for 12 hours.

[0183] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0184] Comparative Example 6

[0185] Preparation of the Secondary Component AgZn Alloy Colloid

[0186] Silver nitrate and zinc nitrate hexahydrate were dissolved in 100 mL of deionized water in a molar ratio of 3:1. Glycerol was added according to its reaction with metal ions (Ag + and Zn 2+) total molar ratio of 10:1, add to the above solution, and stir evenly. Dissolve ammonium carbonate in 100mL deionized water (the molar ratio of ammonium carbonate to the total amount of metal ions is 8:1), and then add it to the above metal ion solution at a rate of 10mL / min. The resulting precipitate is a mixed colloidal solution of silver hydroxide and zinc hydroxide. Electron microscopy characterization shows that the size of the mixed nanoparticles is about 40-60nm.

[0187] Add the third-level component precursor calcium nitrate to the above-mentioned second-level component colloidal solution, stir for sufficient adsorption, and then add the first-level component MoO3 to the above-mentioned second-level component colloidal solution that has adsorbed the third-level component precursor; the amount of the above-mentioned components added is calculated according to the mass ratio of the corresponding active components, first-level component MoO3: second-level component AgZn alloy: third-level component CaO = 85:10:5; after stirring for sufficient adsorption, filter, wash thoroughly, dry, and roast at 500°C in N2 containing 30% H2 for 6h.

[0188] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0189] Comparative Example 7

[0190] Preparation of RuZn alloy colloid as the second component

[0191] Ruthenium trichloride and zinc nitrate hexahydrate were dissolved in 100 mL of deionized water in a molar ratio of 1:3. Glycerol was added according to its reaction with metal ions (Ru 3+ and Zn 2+ ) in a total molar ratio of 10:1, added to the above solution and stirred evenly. Ammonium bicarbonate was dissolved in 100mL of deionized water (the molar ratio of ammonium bicarbonate to the total amount of metal ions was 8:1), and then added to the above metal ion solution at a rate of 10mL / min. The resulting precipitate was a mixed colloidal solution of ruthenium hydroxide and zinc hydroxide. Electron microscopy characterization showed that the size of the mixed nanoparticles was about 50-60nm.

[0192] Add the third-stage component precursor rubidium nitrate to the above-mentioned second-stage component colloidal solution, stir for sufficient adsorption, and then add the first-stage component Sb2O5 to the above-mentioned second-stage component colloidal solution that has adsorbed the third-stage component precursor; the amount of the above-mentioned components added is calculated according to the mass ratio of the corresponding active components, first-stage component Sb2O5: second-stage component RuZn alloy: third-stage component Rb2O=85:10:5; after stirring for sufficient adsorption, filter, wash thoroughly, dry, and roast at 500℃ in N2 containing 30% H2 for 6h.

[0193] The obtained sample was pressed into a sheet with a size of 20-60 mesh, and then added into a fixed bed reactor. Methyl propionate and water were gasified and then entered into the reactor with oxygen and inert gas. The molar ratio of methyl propionate, water and oxygen was 1:2:0.75. The oxygen came from the air, the inert dilution atmosphere was N2, and the inert gas accounted for 50% of the total gas volume. The mass space velocity of methyl propionate on the catalyst was 1h -1 The reaction was carried out at 360°C and 3 atm and monitored online by gas chromatography. The product yield and selectivity after 6 h of reaction are shown in Table 1.

[0194] Table 1 Reaction evaluation results

[0195]

[0196]

[0197]

[0198] From Examples 1-3, it can be seen that the higher the oxygen content, the higher the conversion rate, but the selectivity decreases, and the appropriate range of oxygen content is 0.5-1. From Examples 4-6, it can be seen that the higher the water content, the higher the conversion rate, but the selectivity decreases, and the appropriate range of water content is 1-3. From Examples 7-11, it can be seen that the higher the proportion of inert gas, the higher the conversion rate and the better the selectivity, and the appropriate range of inert gas proportion is 10-70%. From Examples 12-16, it can be seen that the higher the mass space velocity, the lower the conversion rate and the lower the selectivity, and the appropriate range of mass space velocity is 0.3-2h -1. From Examples 17-21, it can be seen that the higher the reaction temperature, the higher the conversion rate, but the selectivity decreases, and the suitable range of the reaction temperature is 310-360°C. From Examples 22-26, it can be seen that the higher the reaction pressure, the lower the conversion rate, and the selectivity also decreases, and the suitable range of the reaction pressure is 1-10atm. From Comparative Example 1 and Example 33, it can be seen that the mechanical mixing of the three-stage active components, although methyl propionate is partially converted, the selectivity is very low. From Comparative Examples 2, 3 and Example 33, it can be seen that the second and third stage components are missing one, although methyl propionate is partially converted, but the selectivity is very low. From Comparative Example 4 and Example 33, it can be seen that the catalyst prepared by co-precipitation of the second and third stage components, although methyl propionate is partially converted, the selectivity is not good. From Comparative Examples 4-6, it can be seen that if the second stage component does not have a good oxidation function, such as components such as AgZn and RuZn alloys, although it can effectively promote the hydrolysis reaction of methyl propionate, methanol cannot be effectively converted into formaldehyde, and cannot effectively catalyze the condensation of formaldehyde and propionic acid to prepare methacrylic acid.

Claims

1. A method for preparing methacrylic acid, characterized in that: In a fixed bed reactor, methyl propionate, water and oxygen are used as reactants. Methyl propionate and water are gasified and mixed with O2, diluted with an inert gas, and react on a catalyst with the three functions of hydrolysis-oxidation-condensation to produce methacrylic acid. The catalyst with the triple function of hydrolysis-oxidation-condensation consists of three components: The first-stage component is an active component with weak acidity to medium-strong acidity, selected from: one or more of natural weak or medium-strong acid clay, metal oxide, weak acid synthetic molecular sieve, and metal phosphate; wherein the natural weak or medium-strong acid clay is selected from kaolin, bentonite, montmorillonite, talc, and natural zeolite; the metal oxide is selected from Al2O3, Ga2O3, Cr2O3, HfO2, ZrO2, TiO2, SnO2, GeO2, Sb2O5, SiO2, and MoO3; the weak acid synthetic molecular sieve is selected from HX, HY, Hβ, SAPO-34, and SAPO-11; the metal phosphate is selected from AlPO4, FePO4, Ti3(PO4)4, Zr3(PO4)4, BiPO4, and Zn3(PO4)2, The second-stage component is a weakly alkaline active component with oxidation function, selected from: CeO2, Pr6O 11 , Tb4O7, V2O5, Co3O4, Fe2(MoO4)3 and mixtures thereof; The third-stage component is an active component with medium to strong acidity or alkalinity or both acidity and alkalinity, selected from: WO3, Nb2O5, Ta2O5, B2O3; one or more of Cs2O, Rb2O, SrO, CaO, BaO, La2O3, Ba(OH)2, and heteropolyacids; wherein the heteropolyacid is selected from phosphotungstic acid, phosphomolybdic acid, silicotungstic acid; SO4 2- / TiO2、SO4 2- / ZrO2、SO4 2- / one or more of Fe2O3, SO4 2- / TiO2 is the carrier in TiO2, in which SO4 2- The loading amount is 5-40 wt%, SO4 2- / ZrO2 is the carrier of ZrO2, in which SO4 2- The loading amount is 5-40 wt%, SO4 2- / Fe2O3 is the carrier in which SO4 2- The loading amount is 5-40 wt%; The preparation method of the catalyst is as follows: firstly prepare a colloidal solution of the second-stage component, then adsorb the third-stage component onto the colloidal solution of the second-stage component, finally load the colloidal solution adsorbed with the third-stage component onto the first-stage component by electrostatic adsorption or impregnation, and finally calcine the solution at a temperature of 400-800°C for a time of 4-24 hours; The molar ratio of methyl propionate, water and oxygen is: 1:(1-10):(0.5-2); The inert gas includes: one or more of N2, Ar, and He; The inert gas accounts for 5-90% of the total volume of the total gas; The mass space velocity of methyl propionate on the catalyst is: 0.2-4 h -1 ; Reaction temperature: 250-450 °C; Reaction pressure: 0.5-30 atm.

2. The method according to claim 1, characterized in that: Oxygen is provided by pure oxygen or air.

3. The method according to claim 1, characterized in that: The molar ratio of methyl propionate, water and oxygen is: 1:(1-5):(0.5-1); The inert gas accounts for 10-70% of the total volume of the total gas; The mass space velocity of methyl propionate on the catalyst is: 0.3-3 h -1 ; The reaction temperature is: 300-400 °C; the reaction pressure is: 1-15 atm.

4. The method according to claim 1, characterized in that: The molar ratio of methyl propionate, water and oxygen is: 1:(1-3):(0.5-0.75); The inert gas accounts for 20-50% of the total volume of the total gas; The mass space velocity of methyl propionate on the catalyst is: 0.3-2 h -1 ; The reaction temperature is: 310-360 °C; the reaction pressure is: 1-10 atm.

5. The method according to claim 1, characterized in that: The catalyst having the three functions of hydrolysis-oxidation-condensation has the following structural characteristics: The first-stage component has an active ingredient that catalyzes hydrolysis; the second-stage component has an active ingredient that catalyzes oxidation; and the third-stage component has an active ingredient that catalyzes condensation. The second-level components are only distributed on the first-level components, and the third-level components are only distributed on the second-level components.

6. The method according to claim 1 or 5, characterized in that: In the catalyst having the triple functions of hydrolysis-oxidation-condensation, the second-stage component accounts for 15-30 wt% of the total mass of the catalyst, the third-stage component accounts for 1-10 wt% of the total mass of the catalyst, and the rest is the first-stage component.

7. The method according to claim 6, characterized in that: In the catalyst having the triple functions of hydrolysis-oxidation-condensation, the second-stage component accounts for 25-30 wt% of the total mass of the catalyst, the third-stage component accounts for 5-10 wt% of the total mass of the catalyst, and the rest is the first-stage component.

8. The method according to claim 1, characterized in that: The calcination temperature during the catalyst preparation process is 600-800°C, and the calcination time is 4-12 h.

Images